Very often I'm building overview pages with sorting and filtering. Here I always miss an easier way to create tags/categories. Right now every tag must be an independent document, which means it clutters the Documents overview page. I would love if just 1 document could hold a "public group" of items - these items would all be available from other documents with the "Content relationship", just like documents are available.
Issue that it solves:
Much better overview and UX for content editors. Easier to convince clients about using Prismic.
Absolutely, and Collections is great too. But it's still a really slow process to create so many new tags/categories and maintain in individual documents. Much quicker and user-friendly if they were in just one group.